Some of the rules to make the past and past participle of regular verbs are:

1- We use "ed" to make the past of regular verbs. Eg.

2- Verbs ending in "e", we only add "d". Eg.

3- In the case of verbs of only one syllable ending in a vowel plus a consonant, we double the consonant and add "ed". Eg.

4- In the case of verbs of more than one syllable ending in vowel plus consonant, when the stress falls on the last syllable, we double the consonant and add "ed". Eg.

5- When the stress does not fall on the last syllable, we only add "ed". Eg.

6- When a verb ends in "y" preceded by a consonant, it drops the "y" and adds "ied". Eg.